JP2011131230A - Connection structure of metal tube in heat exchanger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain sufficient strength and improve workability when brazing an end of a stainless tube inserted into a connection hole in a connection structure where a metal tube is brazed into the connection hole formed at a metal plate to be connected. <P>SOLUTION: In the connection structure where the metal tube is brazed into the connection hole formed at the metal plate to be connected, the end of the metal tube is inserted into the connection hole from the one surface side of the metal plate to be protruded from the other surface side, a metal interposing member having a stopper pawl is fitted in the end of the protruded metal tube, a brazing metal is melt at an area where the surrounding of the connection hole, the metal interposing member, and thereby the metal tube are closely located, and the metal tube is fixed to the metal plate. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a connection structure in which a metal tube is brazed and connected to a connection hole formed in a metal plate.

The hot water heater shown in FIG. 8 is provided with a gas burner 11 for burning the gas supplied from the gas supply pipe 17 below the appliance body, and above the gas burner 11 is the combustion exhaust gas of the gas burner 11. A primary heat exchanger 10 that absorbs sensible heat is disposed, and a secondary heat exchanger 20 that absorbs latent heat contained in the exhaust gas after the primary heat exchange is disposed above the primary heat exchanger 10. It is arranged.
Furthermore, the lower part of the instrument body is provided with an intake fan 12 that introduces outside air and supplies it to the gas burner 11 as combustion air for the gas burner 11.
The gas burner 11, the primary heat exchanger 10, the secondary heat exchanger 20, and the intake fan 12 are accommodated in a casing of the instrument body. An intake port 13 is opened at the lower part of the casing, and an exhaust port 14 is opened at the upper part.

  Water supplied from the outside is heated by latent heat while flowing through the stainless steel pipe 22 provided in the secondary heat exchanger 20, and is further provided with copper provided in the primary heat exchanger 10. While flowing through the pipe 101, it is further heated by sensible heat and sent from the hot water supply outlet 16 to a bathroom or kitchen caran.

The secondary heat exchanger 20 is housed in a box-shaped casing 21 into which the exhaust gas after the primary heat exchange is introduced in a bent state, and the stainless steel tube 22 has a surface area. In order to increase the size, a flexible tube in which bellows-like irregularities are formed is employed.
One side of the casing 21 is closed by a side plate 23 to which the stainless steel pipe is connected, and openings 231 and 232 are formed on the upper surface and the lower surface for exhaust outflow and inflow.
The side plate 23 is formed with an inflow side header 3 and an outflow side header 4. One end of the stainless steel pipe 22 opens into the inflow side header 3, and the other end opens into the outflow side header 4. Yes.

A conventional connection structure of the stainless steel pipe 22 in the inflow side header 3 will be described with reference to FIG.
In the figure, the inflow side header 3 has been described as an example, but since the outflow side header 4 has the same structure, the description thereof is omitted.
The inflow side header 3 includes a recess 31 formed in the side plate 23 and a lid 32 fixed so as to cover the recess 31.
Each of the plurality of stainless steel tubes 22 is inserted into the connection hole 311 formed in the recess 31 and connected by brazing, the water supply pipe 15 is connected to the lid 32, and the lid 32 is connected to the side plate. 23 is brazed.
With the inflow side header 3 having such a configuration, the water supply supplied from the water supply pipe 15 is distributed to the plurality of stainless steel pipes 22.
One end of the plurality of stainless steel pipes on the outflow side is connected to the recess of the outflow side header 4, and the water supply branched and heated to the plurality of stainless steel pipes joins again at the outflow side header 4. The primary heat exchanger 10 is configured to be supplied.

JP 2005-274028 A

In the secondary heat exchanger 20 configured as described above, in the connection structure in which the end portion of the stainless steel tube 22 is inserted and brazed into the connection hole 311 provided in the inflow side header 3 and the outflow side header 4, the connection hole 311. Because the total area of the connection part between the stainless steel tube 22 and the volume of the brazing material interposed between the two connection parts is small, the strength of the connection part is insufficient, and water leakage occurs due to the influence of a water hammer, etc. There is a problem of the risk that the brazing material is not sufficient around the brazing material and brazing is insufficient.
Further, in the process of manufacturing the secondary heat exchanger 20 having the above-described configuration, in the work of inserting and brazing the end of the stainless steel pipe 22 into the connection hole 311 provided in the inflow side header 3 and the outflow side header 4, Since the stainless steel tube 22 before brazing is easy to come off from the connection hole 311, there is a problem in workability that the brazing work must be performed while supporting the stainless steel pipe 22 so as not to fall off.

In view of the above problems, in the present invention, in a connection structure in which a metal tube is brazed and connected to a connection hole formed in a metal plate, the end of the stainless tube is inserted into the connection hole and brazed. The purpose is to obtain sufficient strength and improve workability.

Claim 1 of the metal pipe connection structure according to the present invention is:
In a connection structure in which a metal tube is brazed and connected to a connection hole formed in a metal plate,
From one side of the metal plate, the end of the metal tube is inserted into the connection hole to protrude from the other side,
A metal interposition member in which a retaining claw is formed is fitted into the end of the protruding metal tube,
A brazing material is melted in a region where the periphery of the connection hole, the metal interposition member, and the metal tube are close to each other, and the metal tube is fixed to the metal plate.
In claim 2,
In a connection structure for brazing and connecting a metal pipe to a header recess formed on a side plate of a casing in a heat exchanger,
Insert the end of the metal tube into the connection hole formed in the recess and project into the header space,
A metal interposition member in which a retaining claw is formed is fitted into the end of the protruding metal tube,
The brazing material is melted in the vicinity of the connection hole, the metal member, and the metal tube, and the metal tube is fixed to the concave portion of the header.
In claim 3,
The metal interposition member is characterized in that an outer edge is formed wider than the connection hole, and a part of the inner edge is formed narrower than the outer periphery of the metal tube.
In claim 4,
In the state where the metal interposition member is fitted into the metal tube, a part of the inner periphery presses against the outer peripheral surface of the metal tube, and the other part of the inner periphery and the outer peripheral surface of the metal tube A gap is formed between the two.
In claim 5,
A flat disc-shaped plate portion is formed on the outer edge of the metal interposition member, and a retaining claw is formed on the inner edge.
In claim 6,
The metal interposition member is characterized in that a flat plate portion is formed on the outer edge and a retaining claw is formed on the inner edge.
In claim 7,
The plate portion and the retaining claw form substantially the same plane when no external force is applied,
When the metal tube is elastically deformed by insertion of the metal tube, the retaining claw rises and abuts on the outer periphery of the metal tube to constitute the retaining member.
In claim 8,
The metal interposition member is characterized in that a flat disk-shaped plate portion is formed on the outer edge, and a pressing portion that is elastically biased toward the center is formed on the inner edge.
In claim 9,
The metal interposition member is characterized in that a flat disk-shaped plate portion formed on the outer edge is formed in an arc shape with a part cut away.

A stainless steel tube or a titanium tube can be used as the metal tube. These metal tubes are preferably bellows-like flexible tubes in which a large number of ridges and grooves are alternately formed in order to increase the surface area.

In claim 1 of the present invention,
In a connection structure in which a metal tube is brazed and connected to a connection hole formed in a metal plate,
From one side of the metal plate, the end of the metal tube is inserted into the connection hole to protrude from the other side,
A metal interposition member in which a retaining claw is formed is fitted into the end of the protruding metal tube,
Since the brazing material is melted in the vicinity of the connection hole, the metal interposition member, and the metal tube, the metal tube is fixed to the metal plate. Even if it is in a state, it is possible to prevent the continuation pipe from falling off, and workability is good.
In claim 2, a connection hole is formed in the concave portion of the header formed in the side plate of the casing in the heat exchanger, and a metal interposition member in which a retaining claw is formed is fitted into the end inserted into the connection hole. Since brazing is performed from the beginning, it is possible to prevent the splint pipe from falling off even before brazing, and the workability is good.
In addition, since the brazing material is melted in the vicinity of the connection hole, in the region where the metal member and the metal tube are close to each other, the strength of the brazed portion of the metal tube is increased, and an external force such as water hammer is applied. It is hard to crack and the reliability of the connection part is improved.
According to a third aspect of the present invention, since the outer edge of the metal interposition member is formed wider than the connection hole, the metal interposition member is securely brazed around the connection hole. In addition, since a part of the inner edge of the metal interposition member is formed narrower than the outer periphery of the metal tube, when the metal interposer is inserted into the metal tube, it is inserted while undergoing elastic deformation, and the retaining claws formed on the metal interposition member are Since it is caught on the outer periphery of the metal tube, the metal tube is prevented from falling off even in the state before brazing.
According to a fourth aspect of the present invention, in the state where the metal interposition member is fitted into the metal tube, a part of the inner edge presses against the outer peripheral surface of the metal tube, and the other part of the inner edge and the metal tube Since a gap is formed between the outer peripheral surface and the brazing material, the brazing material also wraps around the gap, thereby enabling more reliable brazing.
In Claim 5, since the flat disk-shaped board part is formed in the outer edge of the said metal interposed member, and the retaining claw is formed in the inner edge, it is connected to the casing by the said board part, The said retaining claw Can hold the metal tube.
In the sixth aspect of the present invention, since the metal interposed member has a flat plate portion formed on the outer edge and a retaining claw formed on the inner edge, the plate portion is not limited to a circle but may be flat. .
According to a seventh aspect of the present invention, the plate portion and the retaining pawl form substantially the same plane when no external force is applied, and the retaining pawl rises by receiving elastic deformation due to insertion of the metal tube. Since it is configured so as to form a retaining stopper by being placed on the outer periphery, the storage space can be saved in a storage state where no external force is applied.
In the eighth aspect of the present invention, the metal interposition member is formed with a flat disk-shaped plate portion on the outer edge and a pressing portion elastically biased toward the center on the inner edge. Even if the metal interposition member has a structure that does not rise, the inner metal tube can be held.
In the ninth aspect of the present invention, the flat plate-like plate portion formed on the outer edge of the metal interposition member is formed in an arc shape with a part cut away, and thus has a shape similar to a C-type washer. You can also

It is side surface sectional drawing of the heat exchanger which implements the connection structure of the metal pipe in the heat exchanger which concerns on this invention. It is sectional drawing explaining the connection hole of the recessed part of the header which is the principal part of the said heat exchanger. It is sectional drawing of the state which inserted the stainless steel pipe | tube in the connection hole of FIG. It is a top view of the washer fitted in the edge part of a stainless steel pipe. It is sectional drawing of the state which fitted the washer of FIG. 4 in the stainless steel pipe | tube of FIG. It is sectional drawing of the state which brazed the state of FIG. It is a top view of the metal intervention member of various forms. It is sectional drawing explaining the schematic structure of the water heater of this invention and a prior art example. It is sectional drawing of the heat exchanger of a prior art example.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings, taking as an example a metal tube connection structure in a heat exchanger of a water heater.
The connection structure of the metal pipe in the embodiment of the present invention can be adopted in the water heater 1 provided with the secondary heat exchanger, similarly to the conventional one shown in FIG.
The basic configuration including the gas burner 11, the primary heat exchanger 10, the secondary heat exchanger 20, the intake fan 12, the casing 21, the intake port 13, the exhaust port 14, the stainless steel tube 22, and the copper tube 101 is illustrated in FIG. Since it is the same as that of 8 and 9, description about the fundamental structure is abbreviate | omitted and the secondary heat exchanger 20 is demonstrated.

As shown in FIG. 1, the secondary heat exchanger 20 is
A stainless steel tube 22 is accommodated in a bent state inside a box-shaped casing 21 into which the exhaust gas after the primary heat exchange is introduced. The stainless steel tube 22 has bellows-like irregularities in order to increase the surface area. The formed flexible pipe is adopted.
One side of the casing 21 is closed by a side plate 23 to which the stainless steel tube 22 is connected, and openings 231 and 232 are formed on the upper surface and the lower surface for exhaust outflow and inflow.
The side plate 23 is formed with an inflow side header 3 and an outflow side header 4. One end of the stainless steel pipe 22 opens into the inflow side header 3, and the other end opens into the outflow side header 4. Yes.
It is also possible to use other metal pipes having excellent corrosion resistance such as titanium pipes in place of the stainless steel pipes.

The inflow side header 3 includes a recess 31 formed in the side plate 23 of the casing 21 of the heat exchanger 2 and a lid 32 fixed so as to cover the recess 31.
The lid 32 is formed with a flange-like flange, and after a stainless steel tube, which will be described later, is brazed, the flange is brazed to the surface of the side plate around the recess to form a watertight header. .
Here, the inflow side header 3 will be described as an example, but the outflow side header 4 has the same structure, and the description thereof will be omitted.

Each of the plurality of stainless steel tubes 22 is inserted into the connection hole 311 formed in the recess 31 and connected by brazing in a state where the washer 7 having a retaining claw is fitted thereinto, A water supply pipe 15 is connected to 32, and the lid 32 is brazed to the side plate 23.
With the inflow side header 3 having such a configuration, the water supply supplied from the water supply pipe 15 is distributed to the plurality of stainless steel pipes 22.
The recesses of the outflow side header 4 are connected to one end on the outflow side of the plurality of stainless pipes 22, respectively. In the outflow side header 4, the water supply branched and heated to the plurality of stainless pipes 22 joins again. Then, it is configured to be supplied to the primary heat exchanger 10.

Next, the brazing structure of the stainless steel pipe in the header, which is a feature of the present invention, will be described step by step.
As described in the background art, a plurality of connection holes 311 are formed in the bottom surface of the concave portion 31 of the header as shown in FIG.
Next, as shown in FIG. 3, the end of the stainless steel tube 22 is inserted into the connection hole 311 and the washer 7 having the retaining claw 71 as shown in FIG. 4 is shown in FIG. As shown, it fits into the end protruding into the internal space of the header.
Similarly, all of the plurality of stainless steel tubes 22 are respectively inserted into connection holes 311 formed on the bottom surface of the header, and a retaining claw 71 is formed at each end protruding into the internal space of the header. Fit the washers 7 respectively.
In the outflow side header 4 as well as the inflow side header 3, all of the plurality of stainless steel pipes 22 are respectively inserted into connection holes 311 formed on the bottom surface of the header, and protruded into the internal space of the header. A washer 7 on which a retaining claw 71 is formed is fitted into each end.
The washer 7 has a configuration corresponding to the metal interposition member described in the claims, and is not limited to the washer, and is formed of a metal that is formed with a retaining claw and can be fitted into the end of the metal tube. The shape is not particularly limited as long as it is a member.

  As shown in FIG. 5, in the state where the washer 7 having the claw 71 formed on the end of the inserted stainless steel tube 22 is fitted, the tooth-like member 711 at the tip of the claw 71 formed in the retaining direction Even if the periphery of the stainless steel tube 22 is caught and brazed, it is possible to prevent the stainless steel tube 22 from falling out of the header.

Next, when brazed in the state shown in FIG. 5, the brazing material is between the surface of the washer claw and the stainless steel tube, the space behind the washer claw, the gap between the back side of the washer and the immediate plate, and the back side of the side plate. Then, the stainless steel tube wraps around the surface of the stainless steel tube and the state shown in FIG. 6 is established, and the stainless steel tube and the side plate are securely and firmly connected and fixed.
In this way, since the volume of the brazing material used for brazing is increased, more reliable brazing is realized and the strength of the connecting portion is increased.
In addition, since the brazing material sufficiently turns to the back surface of the side plate, more reliable brazing can be realized.

Next, the kind of metal interposition member (washer) used for this invention is demonstrated with reference to FIG.
The metal interposition member 7A shown in FIG. 7 is of a shape having a circular outer edge and a plurality of retaining claws formed on the inner edge.
The metal interposition member 7B shown in FIG. 7 has a rectangular outer edge shape and is of a shape type in which a plurality of retaining claws are formed on the inner edge.
The metal interposition member 7C shown in FIG. 7 does not stand up in a state where no external force is applied, forms substantially the same plane as the plate portion, and is elastically deformed by insertion of a metal tube. It is a type that rises up and is placed on the outer periphery of the metal tube to constitute a stopper.
The metal interposition member 7D shown in FIG. 7 is of a type in which a pressing portion that is elastically biased toward the center is formed on the inner edge of the metal interposition member.
The metal interposition member 7E shown in FIG. 7 is of a type in which the flat disk-shaped plate portion formed on the outer edge is formed in an arc shape with a part cut away.

The connection structure according to the present invention is not limited to the connection structure of a metal tube in a heat exchanger, and can be widely applied to a connection structure in which a metal tube is brazed and connected to a connection hole formed in a metal plate.

1 Water heater 11 Gas burner,
10 Primary heat exchanger,
20 secondary heat exchanger,
21 casing,
22 stainless steel pipe,
101 Copper tube 23 Side plate 3 Inflow side header 4 Outflow side header 5 Recessed portion 6 Lid 61 Flange 7 Washer 71 Retaining claw 72 Plate portion

Claims (9)

In a connection structure in which a metal tube is brazed and connected to a connection hole formed in a metal plate,
From one side of the metal plate, the end of the metal tube is inserted into the connection hole to protrude from the other side,
A metal interposition member in which a retaining claw is formed is fitted into the end of the protruding metal tube,
A metal tube connection characterized in that the metal tube is fixed to the metal plate by melting a brazing material in a region where the periphery of the connection hole, the metal interposition member, and the metal tube are close to each other. Construction. In the connection structure of the metal tube that brazes and connects the metal tube to the concave portion of the header formed on the side plate of the casing in the heat exchanger,
Insert the end of the metal tube into the connection hole formed in the recess and project into the header space,
A metal interposition member in which a retaining claw is formed is fitted into the end of the protruding metal tube,
A metal tube comprising: a brazing material melted in a region where the periphery of the connection hole, the metal interposition member, and the metal tube are close to each other; and the metal tube is fixed to a concave portion of the header. Connection structure. 3. The metal pipe connection structure according to claim 1, wherein an outer edge of the metal interposition member is formed wider than the connection hole, and a part of the inner edge is formed narrower than an outer periphery of the metal pipe. In the state where the metal interposition member is fitted in the metal tube, a part of the inner edge presses the outer peripheral surface of the metal tube, and the metal interposing member is placed between the other part of the inner edge and the outer peripheral surface of the metal tube The metal pipe connection structure according to claim 1, wherein a gap is formed in the metal pipe. 5. The metal pipe connection structure according to claim 1, wherein a flat disc-shaped plate portion is formed on an outer edge of the metal interposition member, and a retaining claw is formed on the inner edge. 5. The metal pipe connection structure according to claim 1, wherein a planar plate portion is formed on an outer edge of the metal interposition member, and a retaining claw is formed on an inner edge. 6. The plate portion and the retaining claw form substantially the same plane when no external force is applied,
7. The metal pipe according to claim 5, wherein the retaining claw rises by being elastically deformed by insertion of the metal pipe and abuts on an outer periphery of the metal pipe to constitute a retaining structure. Connection structure. 7. The metal interposing member according to claim 5, wherein a flat disk-shaped plate portion is formed at an outer edge, and a pressing portion elastically biased toward the center is formed at an inner edge. Metal tube connection structure as described. 6. The metal pipe connection structure according to claim 5, wherein the metal interposition member is formed in an arc shape in which a flat disk-shaped plate portion formed on an outer edge is partially cut out. .

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